SHELBY COUNTY. | 465 
ity of Piqua, are here abundantly seen — Halysites catenulata, Stroma- 
topora, Asyringtpora, and some species of Favosites. These were exposed 
on the surface. No fossil shells were to be seen. Fragments of crinoid 
stems seemed to compose a considerable portion of the rock, and several 
species of Fenestella abounded. This formation has never been quarried 
here, apparently, for any economical purpose. It is in the neighborhood 
of an excellent limestone belonging higher up, and which furnishes 
lime of the first quality. The Clinton formation furnishes no good 
building stone in this part of the State, and, while it makes the strongest 
kind of lime, it is hard to burn, and heats greatly in slacking, and sets 
rapidly when mixed. It is highly esteemed in paper-mills, where a 
strong lime is desired, as it more readily softens the material used in the 
manufacture of paper. 
The next formation ascending, is that known as the Niagara. It is 
not seen here in actual contact with the preceeding, as the exposure is 
not continuous; but within about a mile of the river, an out-crop of 
stone is observed on and near the banks of the river. A casual exam- 
ination shows that a great change has taken place in the character of 
the stone. We have not only passed to a new formation, but into the 
upper strata of it. The stone is neither well stratified nor compact, and 
not suitable for building purposes. It is porous, comparatively soft, and 
very fossiliferous, and of a light blue color. It is burned here into an 
excellent lime, known locally asthe Pontiaclime. Thestrata of the Niag- 
ara, sO much prized for building purposes, found at Piqua, and also those 
found at Covington, Miami county, belong below this horizon. The su- 
perposition of this quality of stone upon that of the Covington quarries, is 
ocularly demonstrated on the Stillwater. This river rises gradually up 
to the level of and above the stone of the Covington quarries above Coy- 
ington. At the village of Clayton, on the Stillwater, about two miles 
north of Covington, the banks of the river are formed of the same strata 
as those from which the Pontiac lime is made, within about a mile of 
the last exposure of the Clinton, on the Great Miami. The last exposure 
of the Clinton on the Stillwater, is several miles south of Covington; 
and a familiar example of the Clinton stone may be given in the falls of 
the Panther Creek. It will be seen that all that thickness of building 
stone about the town of Covington, and exhibited so well at the falls of 
Greenville Creek, as well as that of the Piqua quarries, belongs above 
the Clinton and below the strata which first appear above it on the 
Miami, near where the “ Pontiac” lime-kilns are situated. The infer- 
ence follows, that if there is any good building stone within Shelby 
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